A popular construction approach gaining increased acceptance uses Structural Insulated Panels (SIPs). SIP construction employs a basic structural unit comprising two rigid faces on either side of a light insulated foam core. This approach requires good adhesion of the faces to the core to form a high strength structural I-beam. Panels of this type are generally joined by means of lumber and nails, but are increasingly connected using steel studs rather than the conventional 2.times. dimensional lumber approach. The junctures of such panels typically employ a lumber spline with nails and screws for joining. One example of this panel joining approach is disclosed in U.S. Pat. No. 4,443,988, issued Apr. 24, 1984.
In order to accommodate electrical wiring chases extending between adjacent panels, the lumber spline must be configured prior to assembly to accommodate the wire chase. For example, holes in the lumber splines which are aligned with the wiring chases in each foam core must be pre-drilled into the spline generally at the factory. This requires matching each panel juncture with a pre-drilled lumber spline and complicates assembly of the building structure. As shown in the aforementioned patent, each spline is inserted in a respective slot formed by the panel's foam core and one of the opposed facings. An adhesive may be applied to the spline prior to insertion in one of the slots. Because of the tight fit between the spline and its associated slot, the adhesive is generally not uniformly applied to the interface between the spline and connected panel, resulting in reduced bonding strength between two adjacent panels. In addition, there is a tendency for two adjacent panels to pull apart while the adhesive is curing resulting in a less secure connection between the panels. Finally, while metal splines may be capable of providing a high strength connection between adjacent panels, metals have high thermal conductivity and result in energy loss when extending between the inner and outer faces of a panel which forms an outer wall of the structure.
The present invention addresses the aforementioned limitations of the prior art by providing an improved panel joining arrangement for structural panels having opposed outer facings and an inner insulating foam core. The inventive panel joining arrangement employs a pair of spaced metal splines, each bonded to the outer facings of adjacent panels and separated by an insulating core material.